Grease actuated ball and socket joint

ABSTRACT

A socket assembly including a housing having a bore; an insert member disposed in the bore, the insert member defining a socket; and a cap attached to the housing proximate an inlet of the bore and having an opening to receive a connecting member that extends into the socket.

TECHNICAL BACKGROUND

The present invention generally relates to ball and socket jointassemblies and more particularly relates to configurations thatfacilitate grease actuated adjustment of such assemblies.

BACKGROUND OF THE INVENTION

Ball and socket joint assemblies are useful in many applications,including connecting rod assemblies, steering knuckle and drag linkassemblies used in vehicles, and for providing pivotal movement betweentools and construction machines to which the tools are attached. FIG. 1shows a conventional ball and socket joint assembly. Socket assembly 100includes a generally cylindrical, hardened steel housing 110 welded tobracket 108 and defining a socket 109 in which a substantially sphericalball 140 may be disposed to form a joint. Socket assembly 100 alsoincludes semicircular shims 112, 113, 114, 115, 116, 117 positionedflush against housing 110 adjacent to the inlet of socket 109. Whileonly three (3) sets of shims are shown in FIG. 1, in many applicationsup to six (6) sets of shims are used. Shims 112-117 provide spacingbetween housing 110 and cap 130, which is tightened by bolts 131, 132,133, 134, 135, 136 against housing 110 through shims 112-117. Bothhousing 110 and shims 112-117 define corresponding openings to receivebolts 131-136.

It is desirable in most applications to maintain a predeterminedtolerance within the ball and socket joint. As ball 140 rotates withinsocket 109, both ball 140 and socket 109 wear to create excess spacewithin socket 109. To account for this wear, socket assembly 100 isadjusted by removing pairs of shims 112-117 to re-establish a proper fitbetween ball 140 and socket 109. This adjustment is difficult to performbecause it requires disassembly of socket assembly 100, includingremoval of bolts 131-136 and cap 130. This disassembly is furthercomplicated by the fact that ball and socket joint assemblies are oftenpositioned in hard to reach places in the vehicles and/or constructionmachines in which they are used. Consequently, the adjustment of socketassembly 100 is many times avoided.

Additional problems accompany the use of socket assembly 100. The use ofmultiple shims 112-117 cause bolts 131-136 to lose their torque duringequipment operation. Grit and debris may build up on shims 112-117 overtime. When bolts 131-136 are torqued onto housing 110, bolts 131-136clamp cap 130 against housing 110, with shims 112-117 sandwiched inbetween. Subsequent vibration, however, may dislodge the debris on shims112-117, thereby reducing the clamping forced applied by bolts 131-136.At a minimum, this requires more frequent adjustments to socket assembly100, but may also result in damage to the equipment and/or safetyconcerns. Damage may also be caused to ball 140 and socket 109 if amachine operator removes too many shims 112-117 from socket assembly 100during adjustment, thereby creating unwanted friction between ball 140and socket 109. Additionally, because housing 110 of conventional socketassembly is made from hardened steel, difficulties are often encounteredwhen attempting to weld housing 110 to other objects.

SUMMARY OF THE INVENTION

The present invention provides a socket assembly that is readilyadjustable without disassembly and that addresses the problems inherentwith the use of shims. Another benefit of the present invention is thatcurrent applications utilizing socket assembly 100 may be retrofittedwith the socket assembly of the present invention. Additionally, thepresent invention enables cap 130 to be replaced with a simpler, morecost effective snap ring retention.

In one form of the present invention, a socket assembly includes ahousing having a bore; an insert member disposed in the bore, the insertmember defining a socket; and a cap attached to the housing proximate aninlet of the bore and having an opening to receive a connecting memberthat extends into the socket.

In another form of the present invention, the socket assembly includes acylinder having a bore; a piston disposed in the bore and having asocket, the cylinder and piston together defining a reservoir, thepiston adapted to moved axially within the bore when a fluid isintroduced into the reservoir; and a cap attached to the cylinder andhaving an opening through which a connecting member extends to bereceived by the socket.

In still another form, the socket assembly includes a cylinder having abore, an inner surface, an open end and a closed end; a piston disposedwithin the bore, the piston having a first end and a second end defininga socket, wherein the inner surface of the cylinder, the closed end ofthe cylinder, and the first end of the piston together define areservoir within the bore, the piston adapted to move axially within thebore when a fluid is provided to the reservoir; and a cap attached tothe cylinder proximate the inlet of the bore and having an opening toreceive a connecting member that mates with the socket.

In yet another form of the present invention, a machine includes aframe; a connecting member coupled to the frame and including a ball;and a movable attachment coupled to the frame by a socket assemblyincluding a cylinder coupled to the movable attachment, the cylinderhaving a bore and a backing member affixed to the cylinder at an end ofthe cylinder distal to an inlet of the bore, a piston disposed withinthe cylinder and having a socket that receives the ball, the piston andthe cylinder together defining a reservoir within the bore, the pistonadapted to move axially within the bore when a fluid is introduced intothe reservoir, and a cap attached to the cylinder proximate the inlet ofthe bore and having an opening through which the connecting memberextends.

In still another form of the present invention, a method of adjusting asocket assembly is provided, the method including the steps of utilizinga socket assembly to connect a movable attachment to a vehicle framehaving a ball coupled thereto, the socket assembly including a cylinderhaving a bore, a piston disposed within the bore, the piston defining asocket that receives the ball, wherein the cylinder and the pistontogether define a reservoir within the bore, and a cap attached to thecylinder to retain the ball within the socket; and introducing a fluidto the reservoir to move the piston axially within the bore.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned and other features and objects of this invention,and the manner of attaining them, will become more apparent and theinvention itself will be better understood by reference to the followingdescription of embodiments of the invention taken in conjunction withthe accompanying drawings, wherein:

FIG. 1 is a perspective view of a ball and a conventional socketassembly;

FIG. 2 is an exploded perspective view of the socket assembly of thepresent invention;

FIG. 3 is a perspective view of the insert member of the socket assemblyof the present invention;

FIG. 4 is a cross-section view of the socket assembly of the presentinvention with a ball disposed in the socket; and

FIG. 5 is a perspective view of a machine implementing the socketassembly of the present invention.

Corresponding reference characters indicate corresponding partsthroughout the several views. Although the drawings representembodiments of the present invention, the drawings are not necessarilyto scale and certain features may be exaggerated in order to betterillustrate and explain the present invention.

DESCRIPTION OF THE INVENTION

The embodiments disclosed below are not intended to be exhaustive orlimit the invention to the precise forms disclosed in the followingdetailed description. Rather, the embodiments are chosen and describedso that others skilled in the art may utilize their teachings.

An exploded view of the socket assembly of the present invention isshown in FIG. 2. Socket assembly 200 includes housing 110, which may bemade out of a weldable-grade material such as steel tubing. Bore 111extends through housing 110, thereby providing housing 110 with an openend 110 a and defining an inner housing surface 118. Bore 111 is largeenough for a generally cylindrical insert member 210 to be insertedtherein. In other words, the diameter of bore 111 is slightly largerthan the outer diameter of insert member 210. Housing 110 also includesmultiple holes 131 b, 132 b, 133 b, 134 b, 135 b, 136 b on the forwardsurface 120 of housing 110 adjacent to the inlet of bore 111. Holes 131b-136 b have interior threads (not shown) and are configured to receivebolts 131-136. An aperture 122 extends through housing 110 into bore 111from outer surface 119 to inner surface 118.

Cap 130 attaches to housing 110 with bolts 131-136, which extend throughholes 131 a, 132 a, 133 a, 134 a, 135 a, 136 a of cap 130 and arereceived by holes 131 b-136 b of housing 110 as indicated above. Inother embodiments of the present invention, cap 130 may be attached tohousing 110 with a snap ring. Cap 130 has an opening 137 through which aconnecting member, or ball stud 141, of ball 140 (FIG. 4) extends whenball 140 is positioned in socket 212 of insert member 210. Cap 130 alsodefines an interior surface 138 that is substantially spherical in shapeto maintain ball 140 in socket 212 and to accommodate the movement ofball 140. Interior surface 138 may include a flange 139 about the innerperiphery of cap 130 to better maintain ball 140 in socket 212.Additionally, because the diameter of ball 140 is greater than thediameter of opening 137, cap 130 may be comprised of two separablesemicircular sections to enable ball 140 to be positioned within socket212.

In an exemplary embodiment of the present invention, backing member 300is affixed (for example, by welding) within the end of housing 110distal from the inlet of bore 111 to form a closed end 110 b (FIG. 4) ofhousing 110. In other embodiments, backing member 300 is affixed to theend of housing 110 distal from the inlet of bore 111 and may comprise aportion of the attachment to which socket assembly 200 is coupled inparticular applications. Backing member 300 includes an opening 302, theuse of which is explained below.

Insert member 210 fits within housing 110 and has a socket 212 forreceiving ball 140. Shown in greater detail in FIG. 3, insert member 210may be machined from a commercial iron product such as steel. In anexemplary embodiment of the present invention, insert member 210 isformed to resemble a piston having an outer surface 220. Outer surface220 includes a first end, or first outer surface portion, 222 and asecond end, or second outer surface portion, 224. The diameter D₂ ofsecond outer surface portion 224 is greater than the diameter D₁ offirst outer portion 222 (FIG. 4). Second outer surface portion 224 mayinclude about its periphery a groove 223 to receive a sealing member 225(FIG. 4), for example, an O-ring, washer, or other object sized to be insliding contact with and to seal against inner surface 118 of housing110. Insert member 210 has a closed rear portion 214 opposite theopening of socket 212, thereby enabling socket 212 to form asubstantially spherical cup within insert member 210. A post 226 extendsfrom the outward facing surface of closed rear portion 214 into opening302 of backing member 300 (FIG. 2). As is further described below,insert member 210 can be easily removed from socket assembly 200 andreplaced when it becomes excessively worn.

The adjustment of socket assembly 200 for wear is best explained withreference to FIG. 4. FIG. 4 depicts a cross-section of socket assembly200 with ball stud 141 extending through opening 137 (not shown) of cap130 and ball 140 positioned within socket 212 of insert member 210. Asis shown, peripheral sealing member 225, inner surface 118 of housing110, backing member 300, closed rear portion 214 of insert member 210and outer surface 220 of insert member 210 together form a closedreservoir 125 within housing 110 into which aperture 122 extends. Toadjust socket assembly 200, a fluid is introduced into reservoir 125through aperture 122. As fluid is pumped into aperture 122, reservoir125 retains the fluid and the mounting pressure of the fluid urgesinsert member 210 and sealing member 225 toward cap 130 as indicated bythe directional arrows in FIG. 4. Consequently, ball 140 remains insubstantial contact with socket 212, even as wear reduces the outerdiameter of ball 140 and increases the interior dimension of socket 212.

In other embodiments of the present invention, peripheral sealing member225 may not be present and closed rear portion 214 of insert member 210may be positioned against closed end 110 b of housing 110. In theseembodiments, diameter D₂ of second outer surface portion 224 of insertmember 210 is designed for a substantially zero-clearance fit withininner surface 118 of housing 110. Reservoir 125 is thereby formed byinner surface 118, first outer surface portion 222 of insert member 210and closed end 110 b of housing 110, and insert member's 210zero-clearance fit with inner surface 118 prevents the fluid inreservoir 125 from escaping between insert member 210 and housing 110.Accordingly, the pressure of the fluid within reservoir 125 causesinsert member 210 to move toward cap 130 to compensate for anywear-induced clearance between socket 212 and ball 140.

In an exemplary embodiment of the present invention, the fluidintroduced into reservoir 125 is a lubricant such as grease or oil, andaperture 122 includes a one-way valve, grease port or grease fitting. Inthis embodiment of the present invention, the lubricant may be providedfrom a pressurized source such as a grease gun. In another embodiment ofthe present invention, aperture 122 is a ¼ turn relief port to which ahydraulic line and corresponding hydraulics are attached. The pressureof the hydraulics is pre-set to a level that corresponds to the desiredfluid pressure within reservoir 125. A pressure sensor is used tomonitor the fluid pressure within reservoir 125, and when the pressurefalls below the pre-set level (thereby indicating that ball 140 andsocket 212 have worn to create additional clearance in socket 212), morelubricant is introduced into reservoir 125 to adjust socket assembly 200until the pressure within reservoir 125 returns to the pre-set level.

As the pressure of the lubricant in reservoir 125 causes insert member210 to move toward cap 130 during an adjustment of socket assembly 200,insert member 210 should move axially. Rotational movement of insertmember 210 is limited by positioning opening 302 and post member 226 foralignment at a location that is offset from the central axis of insertmember 210. In an exemplary embodiment of the present invention, radialmovement of insert member 210 is limited by sizing opening 302 ofbacking member 300 to receive post member 226 with substantially zeroclearance. In other embodiments of the invention, other means may beused to limited the non-axial movement of insert member 210, for exampleby square or rectangular keys or multiple pins.

Socket assembly 200 of the present invention may be used in manyapplications requiring a ball and socket joint connection. One specificapplication in which socket assembly 200 may be used is in a ball andsocket joint connection of a construction machine having any type ofmovable tool, implement, or attachment, for example, a scraper blade, ashovel loader, a boom, etc. Shown in FIG. 5, machine 400 includes amounting frame 410. Mounting frame 410 includes first attachment arm 412and second attachment arm 414. First attachment arm 412 is movablycoupled to hinge member 422 of attachment 420, and second attachment arm414 is movably coupled to hinge member 424 of attachment 420. Frame 410and attachment 420 are further connected by control arm 430, whichpivotally communicates with hinge member 416 of frame 410 and hingemember 426 of attachment 420.

Ball stud 141 with adjoining ball 140 (not shown) is affixed to thefront end of frame 410, and ball 140 is disposed within socket 212 (notshown) of socket assembly 200. Housing 110 of socket assembly 200 iscoupled to bracket 430 of attachment 420. In other embodiments of thisapplication, housing 110 may be secured directly to attachment 420.Housing 110 includes aperture 122 into which fluid is introduced toadjust socket assembly 200. When insert member 210 (not shown) wears andis no longer useful, it may be replaced with a new insert member withoutthe difficulties encountered when attempting to replace housing 110.

While this invention has been described as having an exemplary design,the present invention may be further modified within the spirit andscope of this disclosure. This application is therefore intended tocover any variations, uses, or adaptations of the invention using itsgeneral principles. Further, this application is intended to cover suchdepartures from the present disclosure as come within known or customarypractice in the art to which this invention pertains.

1. A socket assembly comprising: a cylinder having a bore, an innercylinder surface, and a backing member affixed to the cylinder at an endof the cylinder distal to an inlet of the bore, the backing memberincluding an opening; a piston disposed in the bore and having a socketand an outer piston surface including a peripheral sealing member, theinner cylinder surface, the outer piston surface, the peripheral sealingmember, the backing member, and a closed rear portion of the pistondefining a reservoir, the closed rear portion of the piston having anoutward facing surface including a post, the opening of the backingmember being offset from a central axis of the piston to receive thepost; a one-way valve in fluid communication with the reservoir, thepiston adapted to move axially within the bore when a fluid isintroduced into the reservoir; and a cap attached to the cylinder andhaving an opening through which a connecting member extends to bereceived by the socket.
 2. The socket assembly of claim 1 wherein thecylinder includes an aperture that extends into the reservoir and isconfigured to introduce the fluid.
 3. The socket assembly of claim 1wherein the outer piston surface includes a first portion having a firstdiameter and a second portion having a second diameter greater than thefirst diameter.
 4. The socket assembly of claim 1 wherein the connectingmember includes a ball that is disposed in the socket.
 5. A machinecomprising: a frame; a connecting member coupled to the frame andincluding a ball; and a movable attachment coupled to the frame by asocket assembly including: a cylinder coupled to the movable attachment,the cylinder having a bore, an inner surface, and a backing memberaffixed to the cylinder at an end of the cylinder distal to an inlet ofthe bore, the backing member including an opening; a piston disposedwithin the cylinder and having a socket that receives the ball, an outersurface, and a peripheral sealing member, the inner surface of thecylinder, the outer surface of the piston, the peripheral sealingmember, the backing member, and a closed rear portion of the pistondefining a reservoir within the bore, the closed rear portion of thepiston having an outward facing surface including a post, the opening ofthe backing member being offset from a central axis of the piston toinhibit rotation of the piston; a one-way valve in fluid communicationwith the reservoir; the piston adapted to move axially within the borewhen a fluid is introduced into the reservoir through the one-way valve;and a cap attached to the cylinder proximate the inlet of the bore andhaving an opening through which the connecting member extends.
 6. Themachine of claim 5 wherein the outer piston surface includes a firstportion having a first diameter and a second portion having a seconddiameter greater than the first diameter.